A new study shows that using dispersants to clean up oil spills may do more harm than good. When the dispersants (Corexit 9527A and 9500A, used to aid the 2010 Deepwater Horizon cleanup efforts) are combined with oil, the combination becomes 52 times more toxic than oil alone.
The dispersant breaks up the oil into smaller droplets, but co-author of the new study Terry Snell of Georgia Tech, told LiveScience that this “makes it more toxic to the planktonic food chain.”
This was one of the first studies to examine the impact of the oil-dispersant mixture on plankton.
“The levels in the gulf were toxic, and seriously toxic,” said Snell. “That probably put a big dent in the planktonic food web for some extended period of time, but nobody really made the measurements to figure out the impact.”
A decline in plankton could result in population changes all the way up the foodweb.
“This is a cautionary tale that we need to do the science before the emergency happens so we can make decisions that are fully informed,” said Snell. “In this case, the Corexit is simply there to make the oil disperse and go out of sight. But out of sight doesn’t mean it’s safe in regard to the food web.”
“It’s hard to sit by and not do something,” he continued. “But in this case, doing something actually made it more toxic.”
To learn more:
- Check out this article from LiveScience: Dispersant Makes Oil 52 Times More Toxic
- Find the full study, published in the journal Environmental Pollution, here: Synergistic toxicity of Macondo crude oil and dispersant Corexit 9500A® to the Brachionus plicatilis species complex (Rotifera)
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